Chi Huibing, Chen Meirong, Jiao Linshu, Lu Zhaoxin, Bie Xiaomei, Zhao Haizhen, Lu Fengxia
College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Foods. 2021 Nov 16;10(11):2819. doi: 10.3390/foods10112819.
L-asparaginase (E.C.3.5.1.1) is a well-known agent that prevents the formation of acrylamide both in the food industry and against childhood acute lymphoblastic leukemia in clinical settings. The disadvantages of L-asparaginase, which restrict its industrial application, include its narrow range of pH stability and low thermostability. In this study, a novel L-asparaginase from (GmASNase) was cloned and expressed in BL21 (DE3). GmASNase was found to be a tetramer with a monomeric size of 32 kDa, sharing only 32% structural identity with L-asparaginases in the Protein Data Bank database. The purified GmASNase had the highest specific activity of 486.65 IU mg at pH 9.0 and 50 °C. In addition, GmASNase possessed superior properties in terms of stability at a wide pH range of 5.0-11.0 and activity at temperatures below 40 °C. Moreover, GmASNase displayed high substrate specificity towards L-asparagine with Km, kcat, and kcat/Km values of 6.025 mM, 11,864.71 min and 1969.25 mMmin, respectively. To evaluate its ability to mitigate acrylamide, GmASNase was used to treat potato chips prior to frying, where the acrylamide content decreased by 65.09% compared with the untreated control. These results suggest that GmASNase is a potential candidate for applications in the food industry.
L-天冬酰胺酶(E.C.3.5.1.1)是一种知名的制剂,在食品工业中可防止丙烯酰胺的形成,在临床环境中可用于治疗儿童急性淋巴细胞白血病。L-天冬酰胺酶的缺点限制了其工业应用,包括其pH稳定性范围窄和热稳定性低。在本研究中,从[具体来源未提及]克隆了一种新型L-天冬酰胺酶(GmASNase)并在BL21(DE3)中表达。发现GmASNase是一种四聚体,单体大小为32 kDa,在蛋白质数据库中与其他L-天冬酰胺酶的结构同一性仅为32%。纯化后的GmASNase在pH 9.0和50°C时具有最高比活性486.65 IU/mg。此外,GmASNase在5.0 - 11.0的宽pH范围内具有优异的稳定性,在40°C以下具有活性。而且,GmASNase对L-天冬酰胺表现出高底物特异性,其Km、kcat和kcat/Km值分别为6.025 mM、11864.71 min⁻¹和1969.25 mM⁻¹min⁻¹。为了评估其减轻丙烯酰胺的能力,在油炸前用GmASNase处理薯片,与未处理的对照相比,丙烯酰胺含量降低了65.09%。这些结果表明GmASNase是食品工业应用的潜在候选者。